Electrode.



- To all whom it may concern CARL n. KRUEGER, or SCHENECTADY, new YonnnssIeNo-ia TO GENERAL ELECTBIC' COMPANY, A CORPORATION or new YORK.

. ELECTRQDE.

No Drawing. Continuation in'part of application Serial' No. 700,819, fired may 31 'filed June as; 1913.

Be it known that I, CARL; It. Knunenn, a citizen of the United 'States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Electrodes,

of which the following is a specification.

This is a continuation, in part, of my application, Serial Number 700,819, filedMay 31, 1912. a

My invention has reference to are light electrodes of the kind known as luminous arc electrodes and flame arc electrodes in which the luminosity of the are is mainly due'to the presence in the electrode of titanium or cerium or any of their compounds. Electrodes of this character produce an are which is more or less unsteady and it is 1 necessary to incorporate in such electrodes certain materials which fuse and evaporate at a lower temperature than the light-giving material and which act to steady the arc and are therefore spoken of as steadying materials. Of these the alkali saltsare very effective, and sodium and potassium compounds have heretofore beenused for this purpose, and when a yellow light is desired these materials, which impart a yellow color to the are, are satisfactory. When,

however, a white light is desired, as in the case of titaniferous electrodes, or electrodes containing cerium, these salts become ob jectionable. V

I have found that lithium compounds have the same steadying effect on the white are produced by electrodes containing titanium or cerium as do sodium and potassium salts, but with this difference: that lithium compounds do not color the arc flame perceptibly in'any way and particularly do not impart a yellowish color to the same as do sodium and potassium compounds. Lithium gives a dark red spectrum line, but the intensity of the light of that line is so low, being at the far end of the red part of the spectrum, that it is completely hidden by the intense white arc spectra, particularly by the spectrum of titanium. I have further discovered that the use'of lithium com- '3 containing titanium as the light-giving material, has the additional and uneX ected effect of increasing the light intensity of Specification of Letters Patent.

Serial No. 776.241.

the arc; and Ihave' found that this intensi sent whenthe light-giving material is calcium or any of its compounds. j I have further found that the intensifying action of lithium in a titaniferous electrode is not materially diminished by the presencein such electrode of other steadying materials such as sodium, potasslum or barium compounds.

7 My invention, therefore, comprises the use of lithlum compound, such as lithium fluorid, lithium bor'ate, or lithium oXid as a steadying material in white arc light elec' trodes, and as a steadying and intensifying materla'l in titaniferous arc light electrode,

Pas ed Oct. 12, 191 5 1912. I Tthis application whether or not other steadying materials" are also present in such electrode.

Of-the arc electrodes to which my invention is applicable, those in which titanium carbid is the principal ingredient and those in which titanium oXid is used either alone or as an admixture to magnetite, are particularly useful. tory electrodeby mixing 96% of very finely powdered titanium carbid, such as is obtained on the market, with 3% of black oxid of copper and 1% of lithium. fluorid, and 1 The composition vof the titanium carbid which is suitable for usei'n' conjunction-with.

filling the mixture into a thin iron tube.

I have made a satisfacmy invention mayvary widely. For exam I ple, I have used titanium carbid, made in the arc furnace, containing onlya small percentage, say Ger 7% of carbon, and IL have also used titanium carbid which was u made in the resistance furnace andwhich contained a large percentage of carbon, say

25 or 30%. Since the theoretical amount of carbon present in titanium carbid-is ap proximately 20%, it will'be seen that the first-mentioned material contains a large percentage of free,metallictitanium in addition to the-titanium carbid, while infthe second one a substantial percentage of free carbon is mixed with the titanium carbid.-

It willbe understood, therefore, that when. I refer to titanium carbid, I mean such titanium carbid as is ordinarily obtained and in which free titanium or free carbon may be present, rather than to chemically pure titanium carbid, which it is practically impossible to obtain.

The use of cupreous material, such as black oXid of copper, is advantageous in connection with titaniferous materials, since by its use there is formed a conducting film on the arcing face of the electrode, and the formation of a layer of slag which has 'a' tendency to form on electrodes containing titaniferous material is largely avoided. The use of cupreous material, however, is described and claimed in my application, Serial Number 651,878, filed October 16, 1911.

In the titanium carbid electrode the lithium compound serves the double purpose of a steadier which does not color the arc and as an intensifier, as hereinbefore indicated; the amount of lithium compound (1%) is, in this case, very small.

Another luminous arc electrode and to which my invention is eminently applicable, is the so-called magnetite. electrode, usually composed of magnetite 62 parts, rutile 30 parts, chromite 8 parts, and sodium fluorid, about 11% of the total mixture. This mixture, as well as others, containing magnetite, is known in the art as a magnetite mixture. In accordance with my invention I add to the magnetite mixture a small per-' centage from 9;% to 1% of lithium compound, either as a substitute for the sodium fiuorid or in addition thereto. In either case the presence of the lithium compound remarkably increases the intensity of the light emitted by the are. 1

In the magnetite electrode the use of a chromium compound, such as chromite, has heretofore been deemed 'to be important, since it operates, in addition to its function as a restrainer, whereby it lengthens the life of the electrode, also as a steadier; but I have found that when, in accordance with my invention, lithium fluorid is used either in'place of or in addition to sodium fluorid,

the admixture of chromite becomes unnecessary. The magnetlte mlxture 1s preferably densely compacted, as by swaging, in the iron tube in which it is usually filled. The intensifying effect of the lithium, when the chromite is omitted, becomes very remarkable, the candle power of the are increasing 80% and more over that yielded by the ordinary magnetite mixture with the same expenditure of. electrical energy. I With the chromite omitted, the magnetite mixture which gave the increased candle power above ',indicated was composed of magnetite 70 parts, rutile 80 parts, and lithium fluorid, 1% of the total mixture. 1 have found that in any magnetite mixture, the increase of lithium fluorid beyond 1% does not perceptibly further increase the candle power.

As another example of an electrode em bodying my invention, 1 may mention one of the following composition:

Cerium titanium fluorid 10%, Lithium fluorid 5%, Carbon These materials are finely divided and mixed with a suitable binder and molded and baked as is the usual practice. In this electrode the carbon furnishes mainly the conducting vapors forthe arc and such electrodes are more properly called flame electrodes, as distinguished from luminous arc electrodes, in which the lightgiving vapors are the principal medium by which the current is carried from one electrode to the other, as is the case with the titanium carbid electrode, particularly when the titanium carbid is made in the arc furnace and con tains only a small percentage of carbon.

While in theiforegoing T have particularly mentioned lithium fluorid, the other lithium compounds mentioned, namely, lith ium borate and lithium oXid, may advantageously be employed; the term lithium fiuorid is, therefore, here usedas typical of lithium compounds generally.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. An are light electrode containing a material or materials yielding a substantially white flaming or luminous are and a steadier consisting principally of a lithium compound.

2. An arc light electrode containing titaniferous material, and a small percentage of lithium compound.

3. An are light electrode, containing titanium as the preponderating light-giving material, and a small percentage of lithium compound.

1. An are light electrode containing titanium carbid and a small percentage of lithium compound.

5. An arc light electrode composed of a magnetite mixture, and a small percentage of lithium compound.

7 In witness whereof, I have hereunto set my hand this 26th day of June 1913.

CARL R. KRUEGER. Witnesses:

HELEN Onronn, MARGARET A. DELEHANTY.

, Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. G. 

